The invention relates to a support and/or guide roller with axial bearing pins for drawer pull-out or the like, wherein a plastic roller together with the metal axial bearing pin provides a load-transmitting sliding bearing both in the radial and axial directions.
The requirement for quiet and easy operation of drawers presents a problem still not wholly solved for the manufacturer of drawer guide means. The criteria mainly are the high bearing friction between the support and/or guide roller and the axial bearing pin, furthermore the kind of assembly of the bearing pin to the guide rail. A substantial improvement in the quality of displacement already was achieved when using plastic rollers running on a steel bearing pin.
Again, ball bearings are used as rollers, which are partly provided with an outer race surrounded by plastic. Ball bearings can be sized for high loads and are characterized by running lightly; however they are correspondingly expensive.
The easy running of a support and/or guide roller is meant to ensure not only easy displacement for high drawer load, but also the rotation of these support and/or guide rollers should take place when the drawer loads are small, so that the drawer rail shall roll on the support rollers rather than slide off their circumference. The undesired slide effect results in an uneven wear of the roller circumference and therefore bumpy drawer operation.
Nevertheless, because of the cost factor already mentioned, there is the desire to use rollers of wear-free plastic with still better bearing properties in connection with a metal axial bearing pin, preferably made of steel. However, this matching of sliding bearing so far has failed to provide operation which is as light as with ball bearings so as to obtain rotation when there is the least load, as explained above, on the rollers. Among the significant factors for poor running is the relatively large diameter which is required on account of the one-sided assembly to the rail of the furniture proper. It is known in the pertinent trade that rollers shall run the lighter, the larger the diameter of the rolling surface to that of the bearing bore. The diameter of the roller running surface however depends on the conventional dimensions of drawer guide means as desired by the furniture manufacturers. Attempts to use axial pins as thin as possible while remaining as tough as possible have failed due to the possibility of mounting these axial bearing pins only on one side, namely to the vertical and thin sheet metal flange of a guide rail. In order to ensure the bearing pins be sufficiently firmly seated in the sheet metal flange capable of transmitting the required load from the axial bearing pin to the rail for long-term usage, there must be a specific diameter of the resting surface between the riveted pin and the bearing pin. By means of the riveting procedure, this resting surface is pulled against the sheet metal surface of the furniture-body rail, and the anchoring is thus obtained. The diameter of this resting surface previously determined the diameter of the bearing pin which was required furthermore to be provided with a flange on that side which is opposite the rivet pin so that the plastic roller would be axially supported between the rail and said latter flange.
This conventional axial bearing pin further suffers from the drawback of its assembly. The roller must be placed on the axial bearing pin prior to the riveting process, whereby assembly is extraordinarily hampered and the danger of damaging the rollers is incurred.